Vinyl flooring is a major category of product for residential and commercial construction. Polyvinyl chloride (PVC) is the major polymeric material that functions as binder and imparts desired physical properties of vinyl flooring. Vinyl flooring product structures may include single layer products such as vinyl composition tile (VCT) and sheet and tile structures containing more than one layer. In some products, a high performance coating is utilized on the surface of the structure comprising PVC to impart improved scratch resistance.
Most layers of vinyl flooring products also include a plasticizer material to soften and allow processing of the PVC resin. Some liquid polyesters have found limited utility as plasticizers for PVC resins. Plasticizers contribute little to the strength properties of the final PVC layer after processing.
Typically, low molecular weight, liquid esters of aromatic acids such as phthalates and benzoates are utilized as plasticizers in flooring compositions. These plasticizers have enough volatility to be considered Volatile Organic Components in some clean air environments. The phthalate esters in particular are also suspect from an environmental/health perspective due to their possible biological activity.
One high volume, commercial vinyl tile product, VCT, typically comprises plasticizer and a blend of PVC homo-polymer and PVC co-polymer, e.g. vinyl acetate, as binders in the composition. The vinyl acetate co-polymer allows the composition to be melt when mixed in the low intensity mixers typically used in VCT manufacturing. The PVC compositions are typically heated to less than about 150° C. in tile processes utilizing such equipment. Another issue is that the vinyl acetate PVC co-polymer is currently in tight supply.
Recently, the US Green Building Council has established the LEED (Leadership in Energy and Environmental Design) system for scoring points for new commercial construction (Table 1). Under the LEED system, flooring can be used to obtain points if it contains 10% by weight of or more of post-industrial recycle material.
TABLE 1LEED System For New Commercial ConstructionRatingLEED-NCRatingLEED-EBSystemVersion 2.1SystemVersion 2.0MR Credit5% wt = (post-MR Credit 2.110%4.1consumer + ½ post-1 Point(Post-Consumer materials), or1 Pointindustrial)MR Credit10% wt = (post-20%4.2consumer + ½ post-(Post-Industrial materials)1 Pointindustrial)MR Credit 65% wt = (rapidlyMR Credit 2.550%1 Pointrenewable building1 Point(Rapidly renewable materials)materials and products)NC: New Construction; EB: Existing Building; Minimum % wt for each point. The % for both NC and EB is weight percent.For NC 1 point is granted for at least 5% wt of the total of post-consumer and ½ post-industrial. A second point is granted for at least 10% wt of the total of post-consumer and ½ post-industrial. An additional point is granted for at least 5% wt of rapidly renewable building materials and products.For EB 1 point is granted for at least 10% wt post-consumer materials. A second point is granted for at least 20% wt of post-industrial materials. An additional point is granted for at least 50% wt of rapidly renewable materials.
There has been renewed market interest in giving preference to “greener” flooring products based upon this LEED System. The use of renewable materials is of high interest.
There remains a need to develop “greener” flooring products based upon existing product structures/processes, and available recycle or renewable materials. There also is a need to find a binder system for vinyl flooring products that eliminates low molecular weight plasticizers and the need for vinyl acetate co-polymers of PVC in some vinyl tile manufacturing processes.